| Summary: | 碩士 === 國立臺灣海洋大學 === 系統工程暨造船學系 === 104 === In this project, the performance and cavitation extension of the four-blade endplate propeller and the five-blade endplate propeller applying for yacht,with different pitch ratios including 1.0, 1.1 and 1.3 are investigated. The endplate propeller with these pitch ratios has been tested in National Taiwan Ocean University’s (NTOU) medium-sized cavitation tunnel covering a wide range of cavitation numbers (atmosphere, 2.0, 1.5, 1.0, and 0.75) and shaft inclination angles (0 deg, 10 deg, and 12 deg).
It is shown from the test results: For any inclination angles and pitch ratios, the cavitation extension appears on the outer radius of back side at 90 and 120 deg as the cavitation number is lower than 1.0 (about 28.8 kn ship speed). At all pitch ratios, especially lower pitch ratio, thrust breakdown is found when the cavitation number is 0.75. In other words, as the ship speed is above 33kn, it is necessary to reduce the rotating speed to increase the pitch ratio higher than 1.3.Besides,the open water efficiencies of five-blade endplate propeller are higher than those of four-blade one,and are about 3％ higher than those of conventional propeller.
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